#!/bin/bash
# 20260522 ChatGPT
# $Header$
#
# Example:
#   ./run_sync.sh little_boy_blue 14:40
#   ./run_sync.sh childrens_hour 14:40
#   ./run_sync.sh ./little_boy_blue 14:40
#
# Optional with timeout:
#   ./run_sync.sh little_boy_blue 14:40 300
#

set -euo pipefail

if [ "$#" -lt 2 ] || [ "$#" -gt 3 ]; then
    echo "Usage: $0 binary_name HH:MM [run_seconds]"
    echo "Example: $0 little_boy_blue 14:40"
    echo "Example: $0 little_boy_blue 14:40 300"
    exit 1
fi

BINARY="$1"
START_TIME="$2"
RUN_SECONDS="${3:-}"

# If the binary name does not contain a slash, assume it is in the current directory.
case "$BINARY" in
    */*) CMD="$BINARY" ;;
    *)   CMD="./$BINARY" ;;
esac

if [ ! -x "$CMD" ]; then
    echo "ERROR: command is not executable: $CMD"
    echo
    echo "Check with:"
    echo "  ls -l $CMD"
    echo "  chmod 755 $CMD"
    exit 1
fi

TARGET_EPOCH=$(date -d "today ${START_TIME}" +%s)
NOW_EPOCH=$(date +%s)

# If requested time already passed today, assume tomorrow.
if [ "$TARGET_EPOCH" -le "$NOW_EPOCH" ]; then
    TARGET_EPOCH=$(date -d "tomorrow ${START_TIME}" +%s)
fi

SLEEP_SECONDS=$(( TARGET_EPOCH - NOW_EPOCH ))

mkdir -p "$HOME/logs"

echo "Host:         $(hostname)"
echo "Binary:       $CMD"
echo "Now:          $(date '+%Y%m%d_%H%M%S %Z')"
echo "Target time:  $(date -d "@${TARGET_EPOCH}" '+%Y%m%d_%H%M%S %Z')"
echo "Sleeping for: ${SLEEP_SECONDS} seconds"

sleep "$SLEEP_SECONDS"

STAMP=$(date +%Y%m%d_%H%M%S)
SAFE_BINARY=$(basename "$BINARY")
LOG="$HOME/logs/$(hostname)_${SAFE_BINARY}_${STAMP}.log"

{
    echo "SYNC_START_HOST=$(hostname)"
    echo "SYNC_START_BINARY=$CMD"
    echo "SYNC_START_EPOCH=$(date +%s.%N)"
    echo "SYNC_START_LOCAL=$(date '+%Y%m%d_%H%M%S.%N %Z')"
    echo "SYNC_LOG_FILE=$LOG"
    echo "========================================"
} | tee "$LOG"

if [ -n "$RUN_SECONDS" ]; then
    exec timeout "$RUN_SECONDS"s "$CMD" 2>&1 | tee -a "$LOG"
else
    exec "$CMD" 2>&1 | tee -a "$LOG"
fi